How often do you bump the shoulder back?

[Mikecr]

I don't think case necks expand at all to let bullets out. And necks will only expand at points behind the bullet; there's no outward pressure on the case around the bullet;

No, bullets are not forced out of necks. There is no friction on release unless there is absolutely no clearance. Here, pressure would run away to the destruction of a gun.
The entire case expands and it opens fastest where easiest to do so -thinnest neck brass -open on one end, and the necks are of course first to seal.
We have plenty of information telling us this. For one, seating forces, which are often confused with neck tension, do not affect MV. So 'pull forces' do not affect peak pressure. And I can switch back & forth between bare bullets and those coated with tungsten disulphide(incredibly slippery) with no affect to MVs.

But, actual neck tension(bullet grip) absolutely does affect MV.
Actual tension is spring back against bullet bearing. This is what early pressure overcomes.
Nothing to do with friction, pull forces, or any forcing of bullets from necks.

A couple thousandths of ugly runout on .308 Win ammo shot in a SAAMI spec chamber has put 40 bullets inside 2 inches at 600 yards. Had they all been at zero runout, then perhaps the group would have measured zero. Therefore the formula for runout must be 1/6 MOA group enlargement for every .001" of runout. Right?

There is no defining of runout to results. That's not what I'm doing.
My assertion is that runout in a tight chamber fit leads to chambered tensions. A SAAMI spec chamber is likely a long way from tight fitting. Right?
So crooked ammo shooting better in a loose chamber than a tight chamber is totally inline with what I said.

I feel like this now represents hijacking of OPs thread. We're not talking about shoulder bumping.
Let's pull out.

 

[Pdvdh]

It was interesting. The differences of opinion represent some critical thinking. Value in reading experienced shooters/reloaders differing trains of thought and differing approaches/preferences. Thanks for explaining yourselves. The reader can lean either way, or some combination of the differing perspectives.

 

[J E Custom]

I have tried them all.

Now I have settled down to this method.

For my bolt action hunting guns I use a full length sizing die set to 1.5 to 2 thousands shoulder bump. I want all these rounds to chamber easily.

For my bolt action range guns I neck size and about every 5 firings I use a body die.

For my ar range gun I use a full length sizing die set to a 3 thousands shoulder bump.

I anneal after every 5 firings.

That's close to what I do except I only bump the shoulder when chambering becomes an issue.

I feel that there is no one way to size everything, so I size for the use and type of rifle.

As far as bumping the shoulder and neck sizing go's, I size the minimum required for the type of action, quality of the chamber and the needs of the service use to prevent over working the brass and shortening brass life.

I would have to say that most if not all factory chambers need to be full length sized because of there quality and inconsistency. A precision chamber should only require a minimum sizing. (Just enough to make it chamber with minimum effort).

On full or semi autos It is wise to small base size it for reliable functioning.(Small base sizing is dimensionally smaller than full length sizing).

Just my opinion

J E CUSTOM

 

[Pdvdh]

And I can switch back & forth between bare bullets and those coated with tungsten disulphide(incredibly slippery) with no affect to MVs.

Your coated bullets don't shoot with different muzzle velocity than uncoated bullets?

 

[Mikecr]

Your coated bullets don't shoot with different muzzle velocity than uncoated bullets?

I dry prefoul my bores with tungsten after each cleaning. So as far as my bores, a bullet coating makes no difference.
My point is if bullet release had anything to do with neck friction, then muzzle velocity would follow neck friction in itself. It doesn't.

I can significantly reduce seating forces between coated/uncoated bullets with no affect to MV.
I can significantly increase seating forces by roughing squeaky clean necks/bullets with no affect to MV.
But then I can increase LENGTH of neck sizing by 1/16" and MV will go up with it.
This shows that normal bullet release is tied to TENSION, and not friction.

 

[engineer40]

This entire thread is a great reminder of why reloading and shooting accurately is as much of an Art as it is a Science. We all have our own ways and it must be working for all of us, or else we wouldn't keep doing it.

Just a few weeks ago I shot the best group of my life (8 shots in one tiny 1/4 inch hole at 100 yards) using cheap crap brass, not measuring every powder charge just throwing charges, barely even paying attention to how much I was actually sizing the brass, not using bushing dies or even measuring runout, never chronographed to find the ES and SD, rounds fed from a magazine and didn't single load, using a pencil thin 16" barrel (not free floated), not waiting for the barrel to cool at all (just constant firing), using a trigger measured in pounds not ounces, and the scope reticle was so fat it more than covered the bullseye so I just centered it the best I could. And I did it using literally the cheapest AR15 you can even buy ($475 brand new).

That just kind of throws a wrench into everything I thought I "knew" about reloading and accuracy. I couldn't believe it. So I loaded up 20 more just like the originals and easily repeated the accuracy test that coming weekend. Honestly, I still don't understand it. Makes me **** curious though.

(I also decided right then that I will never make a change to this rifle and will never sell it............ and that I should probably stop doing mag dumps with it too )

Sometimes we spend hours doing research and we test something successfully and it makes us feel really smart.

Other times we most likely just get lucky but still take the credit for the accomplishment.

 

[Rack]

You should buy a lottery ticket. Just saying.

 

[Lefty7mmstw]

This entire thread is a great reminder of why reloading and shooting accurately is as much of an Art as it is a Science. We all have our own ways and it must be working for all of us, or else we wouldn't keep doing it.

Just a few weeks ago I shot the best group of my life (8 shots in one tiny 1/4 inch hole at 100 yards) using cheap crap brass, not measuring every powder charge just throwing charges, barely even paying attention to how much I was actually sizing the brass, not using bushing dies or even measuring runout, never chronographed to find the ES and SD, rounds fed from a magazine and didn't single load, using a pencil thin 16" barrel (not free floated), not waiting for the barrel to cool at all (just constant firing), using a trigger measured in pounds not ounces, and the scope reticle was so fat it more than covered the bullseye so I just centered it the best I could. And I did it using literally the cheapest AR15 you can even buy ($475 brand new).

That just kind of throws a wrench into everything I thought I "knew" about reloading and accuracy. I couldn't believe it. So I loaded up 20 more just like the originals and easily repeated the accuracy test that coming weekend. Honestly, I still don't understand it. Makes me **** curious though.

(I also decided right then that I will never make a change to this rifle and will never sell it............ and that I should probably stop doing mag dumps with it too )

Sometimes we spend hours doing research and we test something successfully and it makes us feel really smart.

Other times we most likely just get lucky but still take the credit for the accomplishment.

Reminds me of the best group I have shot this year... .295" at 200 yards... with a 35 whelen shooting a 220 grain speer flat point bullet at 2700 fps from a ruger 77 hawkeye... The only mod on that rifle is a repaired and free floated wood stock... It wasn't a fluke either as the rifle has turned in a bunch of clover-leafs at 100 and 200 lately. The brass is range pick up rem 30-06 ran over an expander ball and loaded. The primers are wlr, the powder is a weighed charge of rl15, the bullets aren't weighed. The scope is a 3x9 burris in ruger rings.

Kinda makes the extra time and effort I put into my longer range rifles' ammo questionable as to whether it is really worth it.

 

[Pdvdh]

You guys should try iron sights, and see if there's a point of diminishing returns in the move to rustic.

 

[engineer40]

You should buy a lottery ticket. Just saying.

You guys should try iron sights, and see if there's a point of diminishing returns in the move to rustic.

Hopefully my post did not come across as me saying I am an expert marksman or a brilliant reloader; neither are true. I simply shared to give an example of how sometimes you can break the known "rules" and still shoot accurately.

I normally spend a ton of time on brass prep, buy the best components, and take painstaking care to make sure every round is identical in every way. I test and then document my results. Then retest and document some more. All of that work, and I normally don't shoot that accurately.

The more I thought about my example over the last few weeks I have decided the "rules" are more like "things to try". I think that neck sizing can be accurate. I think that bumping the shoulder can be accurate. I think that every example that someone has given in this thread on how they resize their brass can be accurate, or else they probably wouldn't keep doing it.

I'll probably never know why that rifle shoots that ammo so accurately. (And that drives me a little crazy).

 

[J E Custom]

Hopefully my post did not come across as me saying I am an expert marksman or a brilliant reloader; neither are true. I simply shared to give an example of how sometimes you can break the known "rules" and still shoot accurately.

I normally spend a ton of time on brass prep, buy the best components, and take painstaking care to make sure every round is identical in every way. I test and then document my results. Then retest and document some more. All of that work, and I normally don't shoot that accurately.

The more I thought about my example over the last few weeks I have decided the "rules" are more like "things to try". I think that neck sizing can be accurate. I think that bumping the shoulder can be accurate. I think that every example that someone has given in this thread on how they resize their brass can be accurate, or else they probably wouldn't keep doing it.

I'll probably never know why that rifle shoots that ammo so accurately. (And that drives me a little crazy).

As you have probably noticed by now, everyone has there preferred method that works for them.

Some (Like myself) look for consistency. One good group does not make an accurate load.

What ever works time after time is what I will gravitate to and stay with until I find something better
that will encourage me to change.

Also some rifles just prefer some method over the other and you have to be flexible if you want the best from your rifle.

At any rate, consistency in your process and your loading can lead to better accuracy.

J E CUSTOM

 

[engineer40]

As you have probably noticed by now, everyone has there preferred method that works for them.

Some (Like myself) look for consistency. One good group does not make an accurate load.

What ever works time after time is what I will gravitate to and stay with until I find something better
that will encourage me to change.

Also some rifles just prefer some method over the other and you have to be flexible if you want the best from your rifle.

At any rate, consistency in your process and your loading can lead to better accuracy.

J E CUSTOM

Once again, I agree with everything you've said J E Custom.

I have reproduced the accuracy on a different day with the same kind of reloaded ammo. (Reloaded and shot using the same procedures). It was more than 1 group.

I will stop talking now because I didn't intend my post to take this thread off track. I was originally just trying to say to the OP; you don't know unless you try. The Rules are more like Guidelines.

 

[Bart B]

Mikecr,

How big are the largest test groups your rifles and ammo produce with their most accurate ammo?

Inches or MOA at range.

 

[tbrice23]

I am not trying to "stir the pot" at all, just sharing a very recent incident. I always use a Redding body die and Lee collet neck size my 6AI cases but the last time I decided to chamber a couple of fired cases to see how tight they were. They chambered just fine, firm but not hard at all. So i neck sized them and loaded my normal load.

I will not be doing that again. Doubled the group size!
ASAP I body sized them and the groups went back to normal.